During the Battle of Singapore in February 1942 the Japanese managed to invade Malaysia causing what Winston Churchill called the "worst disaster" and "largest capitulation" in British military history.
The Allied Forces imposed a trade ban on Japan, and in response, Japan invaded Malaysia to find alternative sources for needed materials to continue its war against the Allied Forces.
The Japanese army was superior to the British in close air support, armor, coordination, tactics and experience, even though they were outnumbered.
The British made a grave mistake in judgement in thinking that the Malaysian jungle was too dense and impassable. The Japanese had a plan to overcome that.
Thousands of bicycle riding soldiers were able to quietly and speedily navigate their way through the jungle and surprise the unsuspecting opposition.
They did not bring their bicycles with on the ships, but confiscated them from the citizens and retailers in Malaysia as they progressed through towns after coming ashore. This meant that there were no demands made on the Japanese war machine as they did not need trucks or ships to transport the bicycles.
These troops could quickly advance by travelling along plantation roads, foot paths and over improvised bridges. This caught Allied Forces defending the main roads and river crossings off guard.
The bicycles could travel faster than withdrawing Allied Forces and often cut off their escape, resulting in 50,000 troops becoming prisoners of war.
It can therefore be said that the bicycle troops were mostly to thank for the success of the Japanese invasion of Malaysia.